<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Web 拓扑拖拽编辑器</title>
  <link rel="stylesheet" href="styles.css">
</head>
<body>
  <div id="toolbar">
    <button id="addNode">添加节点</button>
  </div>
  <div id="editor">
    <svg id="canvas"></svg>
  </div>
  <script src="script4.js"></script>
</body>
</html>
